While BNS and NSBH mergers are not as commonly observed as BBH mergers, they do have important advantages for nuclear astrophysics. The presence of a neutron star means that these systems can potentially be used to constrain the equation of state of cold, neutron rich dense matter [1]} – a crucial source of information about many-nucleon interactions and, potentially, the high-density states of quantum chromodynamics. Additionally, some mergers and post-merger remnants eject material that undergoes r-process nucleosynthesis. The radioactive decay of the ashes of the r-process can then power optical/infrared emission days to weeks after the merger: a kilonova [2]}, [3]}, [4]}. The production site(s) of r-process elements remain(s) very uncertain today, and the observation of neutron star mergers and associated kilonovae may help us solve the long-standing problem of their astrophysical origin. Additionally, some post-merger remnants likely produce collimated relativistic outflows (jets) that are currently believed to be the source of short-hard gamma-ray bursts (SGRBs) [5]}, [6]}. The exact process powering SGRBs is however not well understood, and further observations of neutron star mergers could help us ellucidate how these high-energy events occur in practice. Finally, joint observations of neutron star mergers using both gravitational and electromagnetic waves may also provide additional information about the properties of the merging compact objects, the position of the merging binary, and even the value of the Hubble constant [7]}, [8]}, [9]}, [10]}.
